using System;
 //csc interface_property.cs
 namespace calculate
 {
 
   //interface begins
    interface Ical
    {
     //declare a variable 
      double area
            //get property
       {
      get;
        }
     }
 class clsCircle : Ical
 {
   // to hold the arguments to the methods
     private double m_radius ;
    //constructor 
    public clsCircle(double radius)
    {
    Console.WriteLine(" constructor for radius evoked ");
    Console.WriteLine(" constructor received :  " + radius);
     m_radius= radius;
    //constructor does not return
    }
    //property calculating area of circle
      public double area
      {
      get  { return (3.14 * m_radius * m_radius);}
      }
      //now return the calculated data to the caller
      public override string ToString()
      {
      return("Area=" + area ); 
      }
 }
 class test
 {
 static void Main()
 {
 Console.Write("Enter the radius of a circle ");
 string str = Console.ReadLine();
 double dd = double.Parse(str);
 //feed value to the property
 clsCircle cc = new clsCircle(dd);
 
 
 Console.WriteLine(" Area of a circle " + cc);
 }
 }
  //end of namespace
 }